Hospitals, surgery centers and other medical treatment facilities use a variety surgical and medical instruments and devices that must be cleaned, disinfected, and reused. Such facilities have established a large number of commercially available and commonly employed cleaning agents that can leave trace amounts of the cleaning agent behind on the cleaned surface following a rinse cycle. While trace amounts of cleaning agent residuals, associated most notably with enzymatic cleaners, are within acceptable limits for washing, rinsing, disinfecting and sterilizing of surgical, medical and other devices, the residual components of such cleaning agents represent a surface contamination that may interfere with the functionality of surgical instruments and with the functionality and efficacy of components within a waste treatment system used by the same hospitals, surgery centers and other medical treatment facilities. Common practice within such facilities leads to the use of manual and automatic washer cleaning agents to clean waste treatment systems and other hard surfaces with a corresponding loss of efficacy and service life performance from critical component contamination caused by the trace amounts of cleaning agent residues.
In large medical facilities, surgical and medical instruments and devices are collected in a central location and are washed by hand and/or in an automatic washing machine before being sterilized and repackaged in a sterile container for reuse by medical personnel. Other devices that must be decontaminated may include waste collection systems and other devices that come in contact with bodily fluids and surgical waste streams.
Cleaning, not sterilization (or disinfection), is a first and most important step in any medical instrument processing protocol. Without first subjecting the instruments to a thorough, validated and standardized (and ideally automated) cleaning process, the likelihood that any disinfection or sterilization process will be effective is significantly reduced.
An automated washer/disinfector cleans and decontaminates dirty medical surgical instruments so they can be handled safely, repackaged, and sterilized for a future surgery. The danger of handling instruments contaminated with blood is obvious in this age of hepatitis, CJD and HIV. The procedures for sterilizing medical instruments are based on years of scientific testing of cleaning instruments. If surgical instruments are not clean, the procedures are ineffective. Dried blood on instruments is hazardous to the employees of the hospital and to the next surgical patient upon which the instruments are used.
Cleaning dried blood is much more difficult than cleaning dirt. Blood coagulates, which means it goes from a free-flowing liquid to a solid that contains tough, microscopic fibers called fibrin. These fibers form as the blood coagulates and jam themselves into microscopic irregularities in the surface of the stainless steel instrument. There is a physical attachment of the fibers to the surface through mechanical means, not chemical means as with traditional adhesives. The action is similar to the roots of plants growing into cracks in rocks, anchoring themselves to the surface.
Another factor that makes blood difficult to clean is its ability to become insoluble when heated. Heating causes blood to denature. Denaturing is similar to what happens to eggs cooked in a frying pan. Transparent uncooked egg whites are fairly easy to wash away, but opaque, cooked egg whites are much more difficult to remove from surfaces. Dried, uncooked egg is even more difficult to wash away, as is dried blood, the proteins in blood are similar to albumin proteins in eggs.
Current automatic washing machines are designed to use a variety of enzyme-based cleaning compositions. However, the enzyme-based cleaning compositions must be used under tightly controlled conditions in order to effectively clean and/or disinfect the medical instruments and devices. Often, the enzyme cleaning compositions leave residual enzyme components on the instruments and devices causing a need to re-clean the instruments and devices before they are reused. Also, the enzyme cleaning compositions are not always effective for cleaning hard to reach surfaces of the medical devices and instruments, if the enzyme residue is allowed to remain on the surfaces of the instruments, the enzyme residual may cause premature failure of the instruments. Accordingly, there is a need for improved cleaning compositions for use in cleaning medical instruments and enzyme residue-containing surfaces.
With regard to the foregoing needs, the disclosure provides a medical surface cleaning composition and a method for cleaning waste treatment system components, medical instrument surfaces, and enzyme residue-containing surfaces. The composition includes a residue cleaning agent and a substantially non-water soluble nonionic surfactant having an initial Ross-Miles foam height in an aqueous solution at 25° C. of less than 10 millimeters. A weight ratio of residue cleaner to surfactant on 100 wt. % active ingredient basis ranges from about 0.05:1 to about 0.5:1. The residue cleaning agent and surfactant are biodegradable.
Another embodiment of the disclosure provides a method for cleaning waste treatment system components, medical instruments surfaces, and enzyme residue-containing surfaces. The method includes applying to a surface to be cleaned a composition that includes a residue cleaning agent and a substantially non-water soluble nonionic surfactant having an initial Ross-Miles foam height in an aqueous solution at 25° C. of less than 10 millimeters. A weight ratio of residue cleaning agent to surfactant on 100 wt. % active ingredient basis ranges from about 0.05:1 to about 0.5:1. An amount of composition is sprayed onto the surface that is sufficient to effectively clean and remove residue from the surface. The surface is then rinsed with purified water to remove the composition from the cleaned surface.
An embodiment of the disclosure also includes a method for removing enzyme residue from enzyme residue-containing surfaces. The method includes applying to a surface to be cleaned a composition that includes a residue cleaning agent and a substantially non-water soluble nonionic surfactant having an initial Ross-Miles foam height in an aqueous solution at 25° C. of less than 10 millimeters. A weight ratio of residue cleaning agent to surfactant on 100 wt. % active ingredient basis ranges from about 0.05:1 to about 0.5:1. An amount of composition is sprayed onto the surface that is sufficient to effectively clean and remove residue from the surface. The surface is then rinsed with purified water to remove the composition from the cleaned surface.
Yet another embodiment of the disclosure provides a method cleaning a medical waste treatment system to remove residue and film formation on surfaces of the medical waste treatment system. The method includes injecting into the waste treatment system a composition that includes a residue cleaning agent and a substantially non-water soluble nonionic surfactant having an initial Ross-Miles foam height in an aqueous solution at 25″ C. of less than 10 millimeters. A weight ratio of residue cleaning agent to surfactant in the composition on 100 wt. % active ingredient basis ranges from about 0.05:1 to about 0.5:1. The amount of composition injected into the waste treatment system is sufficient to effectively clean and remove residue from surfaces of the medical waste treatment system. Subsequent to cleaning, the surfaces of the system are rinsed with purified water to remove the composition from the cleaned surfaces.
An advantage of the compositions and methods described herein is that the compositions are not highly corrosive, are low-foaming, and do not rely on the use of enzymatic agents. Enzymatic agents are highly sensitive to alkaline or acid components used in conventional cleaning compositions and to water temperatures. Another disadvantage of enzymatic cleaning agents is that such agents typically leave an enzyme cleaner residue on the cleaned surfaces that can build up over time and cause premature failure of sensitive waste treatment system components and/or medical instruments. The compositions described herein require only a single, substantially non water soluble, non-ionic surfactant and are effective for removing residual enzyme cleaner residues from the surfaces of medical instruments and other devices that were previously cleaned with enzyme cleaning agents.
Another advantage of the compositions and methods described herein is that the compositions leave substantially no detectible residue on the cleaned surfaces. A surface having no detectible residue is a surface that is visually clean to the naked eye and, over time, has no visible build up of residue upon subsequent cleaning with the same cleaning composition.
Another advantage of the compositions described here is that the compositions are optically clear and concentrates of the composition are stable over time, i.e., do not form visible precipitates in an aqueous solution of the concentrate, despite the use of a substantially non-water soluble surfactant. A further advantage of the compositions described, herein is that the compositions have low or no foaming tendencies thereby enabling the compositions to effectively wet the surfaces to be cleaned without interference of foam adjacent to the surfaces. The low foaming tendency of the compositions make the compositions suitable for spray application to the surfaces under turbulent flow conditions. Other advantages may be apparent from the following detailed description.